1. Field of the Invention
This invention generally relates to infusion beverage brewing systems and more specifically to coffee makers and tea makers.
2. Description of Related Art
A wide variety of products are available for making beverages such as coffee or tea. Basically, the brewing process involves bringing a liquid, such as hot water, into contact with an infusible material, such as ground coffee or tea leaves. This process infuses the water with the essence of the infusible material to produce a beverage.
In one category of such systems, particularly adapted for making coffee, an infusible material, such as ground coffee, is placed in an enclosed volume. Heated liquid is directed through the infusible material emerging as the beverage. A receiver, such as a coffee pot, accumulates the beverage. In another category, to which the application is applicable, the liquid and material to be infused are placed in a pot and allowed to steep for a brewing time. After that brewing time expires, the beverage is supposedly ready for consumption. If the beverage is allowed to continue to steep beyond the brewing time, the quality of the beverage can degrade. Typically the individuals characterize the beverages steeped for too long a period to be “too strong” or “bitter.” This problem has resulted in an effort to control the brewing time with particular emphasis on different approaches to terminating any significant interaction between the infusible material and the beverage after the brewing time.
For example, U.S. Pat. No. 5,632,194 (1996) to Lin discloses an infusion beverage brewing system with a beaker and an inner cup for containing boiling water and tea leaves. During the brewing time a ball valve seals an aperture through the bottom of the inner cup. At the end of the brewing time, the inner cup is elevated from its normal position in the beaker. This releases and opens the ball valve so the beverage transfers into the beaker. In this particular approach, the displacement of the ball from its seat establishes a passage through which the beverage passes. If the passage is sufficiently large, the beverage can entrain tea leaves as it transfers into the beaker. Further, this approach requires an individual to hold the inner cup away from the beaker until such time all the beverage transfers into the beaker.
U.S. Pat. No. 5,635,233 (1997) to Levinson discloses a plunger-strainer or “french press” coffee maker. The infusible material and liquid are placed in a container. Then a plunger assembly with a lid is inserted into the beaker. After the brewing time, a plunger assembly is moved in an up and down motion but generally downward for sweeping the material into a volume below the plunger. The plunger includes a foam filter disk which is pushed through the infusible material and forms a closed volume at the bottom of the container for the infused material. However, this material is not impervious to liquid and acts as a filter. Thus, liquid can contact the infusible material and brewing can continue even after the infusible material is confined to the closed volume.
U.S. Pat. No. 5,979,299 to (1999) to Hornsby also discloses a plunger-filter infusion device with a container and a plunger with a resilient plunger head that slides within the container. A cup-like insert is placed in the base of the container with the infusible material. Heated water is poured into the container and after an appropriate brewing time the plunger is slid into the container until it engages the insert. As a result, the infusible material is confined by the plunger head in the insert. Both the plunger head and insert can be removed after the brewing time elapses. The plunger requires specific sealing structures (not shown) that accommodate the difference in diameters between the container and the insert in order to prevent the escape of the infusible material past the periphery of the plunger head.
U.S. Pat. No. 5,478,586 (1995) to Connor discloses a french press-type system characterized by an operation that differs from normal french press operations. In the Connor patent the plunger head is positioned at the bottom of a container during the brewing time. Then the plunger is lifted through the beverage to lift the infusible material to the top of the container. This system relies on peripheral sealing between the plunger and container to prevent the escape of infusible material back into the beverage as the plunger is withdrawn.
In U.S. Pat. No. 6,422,131 (2002) to Brady the plunger in a french press coffee maker includes a filter element that permits the flow of liquid through the plunger without allowing the passage of the infusible material therethrough. A buffer element is situated above the plunger. The buffer element is closely spaced to the plunger. When the plunger is fully depressed, the buffer element decouples the flavored beverage from the infusible material to minimize interaction between the beverage and the material below the plunger after the brewing time has elapsed.
A marketed Bodum Assam brewing apparatus includes a cylindrical insert that is located in a container and has a solid wall portion at the bottom and a perforated intermediate wall portion. As the plunger passes through the insert, it forces the infusible material toward the bottom and eventually captures it in a closed volume at the bottom of the insert. This approach, however, relies upon the effectiveness of a peripheral seal that contacts the interior portion of the cylindrical insert. When the insert passes the solid wall portion, a significant hydraulic pressure can be produced below the insert and force the seal to open. Opening the seal allows at least some of the infusible material, such as tea leaves, to escape back into the beverage.
As will now be apparent, each of the foregoing examples of infusion beverage brewing systems is subject to one or more disadvantages. Some, such as the systems disclosed in the Yin and Hornsby patents, are made with extra elements that complicate the use of the apparatus either by requiring extra parts or specific operations. Others such as the Bodum system and systems disclosed in the Connor and Brady patents provide an apparatus that still allows material to escape into the beverage thereby to continue to brew beyond the desired brewing time. What is needed is an infusion beverage brewing system in which the infusible material can be fully isolated from the beverage after the brewing time elapses thereby to avoid continued interaction between the beverage and the infusible material that could otherwise degrade the quality of the beverage.